Chapter 4 - Atoms and the development of the Atomic Theory


Day 1

Introduction to atoms
  • Individual atoms are too small to see. Seriously, atoms are too small to see in the way that human vision works. In order for us to see something, the object must reflect visible wavelengths of light that can enter the eyes, strike the retina and be decoded by the brain. If there is no light, nothing is visible. Other small objects, such as cells, are too small too see with the naked eye -- but, if the light they reflect is magnified through the series of lenses in a microscope, we can see cells. A cell may be made up of tens of millions or billions of atoms. An individual atom is too small to be seen by any light microscope. The reason for this is that an individual atom is approximately 0.1 - 0.5 nanometers (nm) in diameter depending on the type of element. That is far too small to reflect visible wavelengths of light (400-700 nm). There would need to be hundreds of atoms in a particle large enough to reflect light. Even today, with all the technology available to us, we can't see individual atoms, but we can use computers to create images like the ones below that are accurate representations of atoms made from data other than reflected light.

stm10.jpg
Scanning Tunning Microscope Image
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Atomic Force Microscope


  • In spite of our inability to see atoms, scientists have believed that all matter is made up of these tiny particles for over 200 years and have learned a great deal about their structure and behavior. We will learning about the current information we have about atoms and the evidence that supports the atomic theory.
  • I gave this set of note( ) to students and we talked about the contributions that each of these people made to chemistry. On the first day we covered from Early History up to Antoine Lavoisier and the Law of Conservation of Matter.
  • HOMEWORK: Look at the material in Chapter 4

Day 2

  • LAB - Law of Conservation of Mass
  • Do lab questions and hand in LAB
  • HOMEWORK: Read pp. 92-97

Day 3

  • Collect LAB questions
  • Proust and Law of Definite Proportions
  • John Dalton, Law of Multiple Proportions and Dalton's Atomic Theory
  • Periodic Table - give out and color-code for metals, nonmetals and metalloids like in the image below
    periodic_table.gif
  • HOMEWORK :p. 103 # 22-24, 26-30

Day 4


Day 5



Day 6


Day 7

  • Atomic models through history
  • Neils Bohr and electron energy levels
  • Work on Chapter 4 Review Packet
  • HOMEWORK: study

Day 8

  • TEST on Chapter 4
  • HOMEWORK: Have a great Thanksgiving Break!